Q9

1. Use this data for problems 1-4.

A pediatrician claims that the mean in heights of 10-year-old girls is greater than the mean in heights for 10-year-old boys. A sample of 10 girls had a mean of 60 in. and a standard deviation of 2.5 inches. A sample of 8 boys had a mean of 56 in. and a standard deviation of 1.5 inches. At a level of significance of 0.025, does the evidence support the pediatrician's claim?

Give the hypotheses.

2. Give the critical value(s).

3. Give the test stat.

4. Give the decision and conclusion.

5. Use the given data for problems 5-8.

At a 1% level of significance, an ornithologist wants to test the claim that the average life expectancy of Baltimore Orioles is less than that of Robins. The data are below. What would be the pair of hypotheses?

Baltimore Orioles | Robins

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n = 15 | n = 12

x = 1.40 yrs|x = 1.60

s = .40 yrs|s = .80 yrs

6. What would be the critical value(s)?

7. Give the test stat.

8. Give the decision and conclusion.

9. The head of the Engineering Department at Sumner College claims her graduates have a higher grade point average than those at Compton College. A sample of 80 graduates from Sumner College and a sample of 100 graduates from Compton College is used and their average grade points are calculated. Test her claim at = 0.025.

Sumner College|Compton College

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n = 80|n = 100

x = 3.20|x = 3.15

σ^2 = 0.56|σ^2 = 0.38

10. The afternoon stats section seems to have the same average quiz score as the morning section. A sample of the afternoon quiz scores is:

18 12 13 18 19 19 18

A sample of the morning quiz scores is:

12 13 14 19 18

If you were to test the claim that both sections appear to have the same mean score, what would be the test value?